Tractors may be equipped with a power take off (PTO) that transmits rotary power from an engine to an implement. The most common location for the PTO shaft is at the rear of the tractor, but some tractors have auxiliary PTO shafts at other locations. The direction of rotation, rotational speed, approximate location and exact dimensions of the PTO shaft are standardized to provide ability to interchange between power shafts on various implements made by different manufacturers. PTO shafts typically rotate at 540 rpm, 1000 rpm, 2100 rpm, or more than one speed.
To engage the PTO to the shaft or drive line of a rear mounted implement, the PTO may have the ability to telescope. After the tractor is in proper position, the tractor operator may manually extend the telescoping PTO and employ various coupler devices to couple the PTO to the implement power shaft. This requires getting down off the seat or operator station of the tractor, and it can be quite time consuming to couple the power take off to the implement manually. Coupling a tractor PTO to the driveline of an implement also can be difficult and dirty.
In the past, PTOs have been coupled to implement drivelines using splines to transmit rotational power, along with an additional keeper to secure the coupled parts and resist thrust loads. Often it is difficult to find the correct alignment for the female spline of the drive line and the male spline of the tractor PTO. Sometimes it is necessary for the operator to turn the implement drive line until the correct alignment is found.
After correct alignment is accomplished, the operator still must hold back a driveline locking feature until the implement shaft or driveline is in place. It may be difficult to manipulate the lock back feature or turn the implement driveline to obtain correct alignment between the PTO and the implement shaft.
A need exists for an improved apparatus and method for coupling a PTO on a tractor to the shaft or driveline of an implement. There is a need for greater operator safety and ease of use when hooking up a tractor PTO to the shaft of an implement. There is a need for a self-aligning driveshaft coupler that may be used with standard PTO driveshafts on tractors, and with standard shafts or drivelines on a variety of different implements. There also is a need for a self-aligning driveshaft coupler that does not require any external energy source such as electricity, hydraulics or pneumatics.